Selena Gomez's best friend gave her a kidney this summer

(CNN) — Selena Gomez revealed on Thursday that she received a kidney transplant from her BFF.

The singer posted a photo on Instragram that shows her and fellow actress Francia Raisa holding hands across their hospital beds.

"I'm very aware some of my fans had noticed I was laying low for part of the summer and questioning why I wasn't promoting my new music, which I was extremely proud of," Gomez wrote in the caption." "So I found out I needed to get a kidney transplant due to my Lupus and was recovering."